Hydraulic actuated firing pin for a firearm



March 18, 1958 E. M. HARVEY 2 HYDRAULIC ACTUATED FIRING PIN FOR A FIREARM Filed Aug. 15. 1954 5 Sheets-Sheet 1 IN VEN TOR.

Emile M- HUIVEY Arm/ems r5 March 18, 1958 E. M. HARVEY HYDRAULIC ACTUATED FIRING PIN FOR A FIREARM Filed Aug. 15. 1954 I I5 Sheets-Sheet 2 ZEN- WW H WWWM WW H M March 18, 1958 4 EY 2,826,847

HYDRAULIC ACTUATED FIRING PIN FOR A FIREARM Filed Aug. 15. 1954 s Sheets-Sheet 5 fig. Cl

IN VEN TOR.

v HYDRAULIC ACTUATED rmnaa n PIN FOR=A Earle M. Harvey, Agawam, Mass assign'or to the United States of America asrepresentedby the Secretary or the Army Application August 13, 1954, Serial No. 449,812:

3 Claims. (Cl. 42-69)" (Granted under TitleSS, .UL S. Code (1952), see. 266) The invention described. herein may. be'manufiaetured andv used by or for the Government. for governmental purposeswithoutthe payment of any royalty thereon1=- Thisinvention relates to firinglmechanistns fou automatic firearms and more particularly tofiringpinsWhich are mounted for reciprocablemovement in a breech member.

Difiiculties are oftentimes encountered, when designing firing pins, because of the-problems involving the. length and weight thereof. It isimportant in designingifiring pins thatthe weight be reduced so that'the cartridge will be struck by as light a blow as possible, while still retaining sufiicient strength in the structure to eliminate. breakage.- The matter of length is rlikewise important because by increasing the length of the firing pin the structureis increasingly subjected to fatigue. during operation,.,causingfatigue cracks and resulting breakage.

Further, whenmounting a firing pin in the breech memher, it is. necessary to provide unobstructed space therein axially rearward of the barrel, which is accomplished sometimes at the expenseof other desirabledesign features. It is also difiicult by conventional means to provide offset mounting for the firing pin when such is desired:

Accordingly, it is an object ofthis invention toprovide a firing pin having a flexiblecolumn forvcircuiting obstructions in the breech-member and for facilitating offset mounting.

It is anothero-bject of this invention to provide afiring pin wherein the weight is reduced considerably without sacrificing structural strength.

It is a further object of this invention to provide-a firing pin wherein the length is extendable toany distance without undesirable efiects.

It is a specific object of this invention to provide a firing pin actuatable by self-contained hydraulic means.

It is another specific object of this invention to provide a firing pin device wherein a cartridge striker'member is separated from an actuator member by a cooperating, movement transmittingcolumn of fluid.

The specific nature of the invention as well as other objects and advantages thereof will clearly appear from a description of a preferred embodiment as shownfll in the accompanying drawings in which: 7

Fig. 1 is a fragmentary, longitudinal, cross se'cti'onal view of the rear end of the firearm showing the firing pin of this invention mounted in the breech mechanism thereof in one embodiment and in a firing position;

Fig. 2 is an enlarged view taken along line 22 of Fig. 1;

Fig. 3 is a longitudinal, crosssectional view of the breech member showing the firing pin in another embodiment and in a retracted battery position;

Fig. 4 is an enlarged, fragmentary view of the embodiment illustrated in Fig. 3 but showing the firing pin in forward cartridge firing position; and

Fig. 5 is a longitudinal, cross-sectional view of still another embodiment of the firing pin of this invention.

Shown in the figures, is a firearm having a barrel 12 with a conventional cartridge chamber 14, a receiver 16 and a.

aszasrz Bat-tented: M m-r1 85; 1 958 breech:.rrrechanism. 18: Breech: mechanism 1 I8 1 includes .1 a carrier 20 v mounted in: receiver lfiforf slidabl'e movement betweema recoil and a batterypositionianda bol1r22 mounted. for. limited slidable movement insuchiscarrier as is disclosed in Patent No. 2,6'26,474:to .-John hLoch'head.

Extending forwardly from thermal end oftbolti 22 in Figs. 1,. 2 3 and-"4is a longitudinal. bore. 24,. which. is tapered at the front end,yas noted at21, to blend withi a forwardlyextending smaller diameter portion1 23'; Inthe embodiment illustrated in'Fig. 5, bore 26is -oflfsetlitoia lower level. ati the front end: with taper portion'zzliand smaller diameter portion 23 being contained in ta p1u'gc25 whichrisasecured as;by press: fit in. the frontzportion' oftsuch offset portion. r

In the" embodiments-illustratedrinziFigst 1', 2: and 5, a port 28- extends from the top side ofb'ol't 2'2ito bore z l to provide means of fillin'ge such bore with. hydraulic fluid 59.

Port zfi is counterbored'from the 'top, as noted at 30; to forma shoulder 32; and such? counterbore portion is threadedrto receiveca: screw 34. A gasket 36 is provided between'shoulder 32: andfiscrew 3T4r'so that tighteningscrew 34 thereagainstirnakes:portiZB'fluid tight. l

Mounted forrslidable movement in the. front" endof bore- 24 and smaller: di'ameterfportionl3 is avconventionally' IIOiIIlltidi cylindricall cartridge striker member 38 which is-rinstallediin.ttheernbodiment illustrated in Figs.- 1

and 2 fromvthe" rearrendii. andiir'rsbore 26 illustrated in Fig; 52 from; theefront end. with? plug 251 installed" after installatiomv slidably mounteditransversely through cartridge. strikermember 38:.is1 a1 retractor mem'ber 40 having an. end. 42=cooperably received inf an'i arcuately terminated recess 44 in carrier: 20' onone side ofbolfZZ and an. opposite end? 43 similarly, received inian arcuately terminated recess=45 inthe carrier onztlie oppositesid'e of the bolt. A planar surface-41 extendslongitudinally forward from arcuateirecess 4'5; Providedlon retractor 40, intermediate ends 42' and 43 is acam surface 4'6lwh'ich isengageable. with an angular surface 47 in cartridge striker" member. 38; As. taught" by the: aforementioned patenti toJ'ohnL. Lochhead; when b'oltl2'2 isinbatt'ery position1retract0r'40 is move'dlby the engagement of end 42 thereofiwith the rear? arcuate:end of recess. 43 :so that cam surface 46 is moved awayfrom angular surface 47, freeing cartridge striker member 38 for actuation by a hammer'56 to firea cartridge 49- i'n charnber' 1.4. During theensuing recoil of breech mechani'sm l' end 43 ofretractor 40" cammingly engages the forward 'end of recess 45 andis moved-thereby onto surface' 41', wherebycam surface 4'6'engages angular surface 47 on cartridge striker member 38 for camming retraction thereof witli-the-engagernent of end 43 with surface; 41 maintaining such retractorinla: retracted position} Slidablymounted'ini the rear end of bore z llin Figsg-l, 2 andcb'orer26i in-Fig. 5, is a cylindi'ical actuator member 48 which'isaprovided' with anannular groove 50: Apin 52 is transversely mountedthrough .bolt:22'wto -bei received by groove 50 for limiting the reciprocablemovement-of actuator 48 with such movement being sufiicient to actuate cartridge striker member 38 to fire cartridge 49 when transmitted thereto as hereinafter explained. Pin 52 is so arranged in bolt 22 that the rear end of actuator 48 extends rearwardly from bolt 22 to be engageable by hammer 56.

In the embodiment illustrated in Figs. 1, 2 and 5, there are fixedly secured to the facing ends of actuator 48 and cartridge striker member 38 cup-like hydraulic seals 57 and 58, respectively, or any other suitable type of seal which will maintain in bore 24 a column of hydraulic fluid 59, while being slidably moved therein. Whereby, such column of hydraulic fiuid 59 is responsive to reciprocal movement of actuator 48 and cartridge striker member 38 for actuation of the opposite one of such actuator or cartridge striker member.

In the embodiment illustrated in Figs. 3 and 4, the rear end of bore 24 is counterbored, as noted at 60, to receive as by press fit an insert 62. Provided in insert 62 is a passageway 64 which is longitudinally aligned with bore 24. A hole 88 provides outside communication with passageway 64 and such hole is counterbored from the top side of bolt 22 part way into insert 62 and is threaded to receive screw 34 which aids in securing insert 62 in bolt 22 as Well as incloses such hole. 1

The front of passageway 64 is counterbored and threaded, as noted at 70, and such counterbore portion threadably receives a diaphragm member 72. The rear end of passageway 64 is counterbored, as noted at 73, and is arranged to threadably receive a diaphragm member 75 in the front portion with an actuator 92 mounted rearwardly thereof. A pin 78 is mounted transversely through insert 62 for cooperation with an annular groove 94 in actuator 92 to limit the reciprocation thereof.

Diaphragm members 72 and 75 .are provided with axial holes 74 and 77, respectively, and fixedly secured to the facing ends of each of such diaphragm members are diaphragms 76 and 79, respectively. Diaphragms 76 and 79 are distensible in the area of holes Hand 77 and form liquid tight seals to secure in passageway 64 the column of hydraulic fluid 59 which fills such passageway when diaphragm members 72 and 75 are tightened against the shoulders 83 and 84 formed, respectively, by the counterbores 70 and 73. The ends of holes 74 and 77, adjacent the associated diaphragms 76 and 79, are countersunk, as noted at 80, to permit deflection of the diaphragms for displacement of the column of hydraulic fluid 59 in passageway 64. The total of such displacement is the amount of the deflections of diaphragms 76 and 79 into their respective countersunk portions 80 and such displacement is, arranged to be equal to the movement of actuator 92 permitted by pin 78 in groove 94.

Extending from the front end of actuator 92 is a stem portion 81 which is slidably received by hole 77 in diaphragm member 75 to engage diaphragm 79 for deflection thereof. Extending from the rear end of a cartridge striker member 98, which is similar to the aforementioned cartridge striker member 38, is a rod portion 82 which is slidably received by hole 74 in diaphragm member 72 for contact by diaphragm 76 during deflection thereof. Whereby, actuator 92 and cartridge striker 98 are simultaneously responsive to movement of the other.

Operation In theembodiment illustrated in Figs. 1, 2 and 5, bolt actuator 48 and cartridge striker member 38 are placed in their rearward positions in bolt 22 so as to be in their proper relationship and then bore 24 or 26 is filled with hydraulic fluid 59 through port 28 up to the level of shoulder 32. Screw-34 is then installed and tightened When breech member 18 is in battery position an hammer 56 is released to strike actuator 48, such actuatc is impelled forwardly forcing the column of hydrauli fluid 59 ahead of seal '57 against seal 53 on cartridg striker member 38. Thereby, cartridge striker member 3 is impelled against the primer of cartridge 49 in chambe 14 of barrel 12 causing such cartridge to fire. In th resulting recoil of breech mechanism 18, retractor 49, a hereinbefore explained, actuates cartridge striker mem ber 38 rearwardly with the column of hydraulic fluid 5! simultaneously transmitting such movement to actuato:

The embodiment illustrated in Figs. 3 and 4 function: the same way in bolt 22, the difference being that movement is transferred simultaneously between actuator 92 and cartridge striker member 98 by the responsive distentions of diaphragms 76 and 79 which transmit and respond to movement of hydraulic fluid 59 in passageway 64.

From the foregoing it is clearly apparent that there is here provided an improved firing pin device which is easily circuitable around obstructions in the breech member, is easily adapted to offset mounting, permits unlimited length without undesirable effects, provides reduction in weight, is easily fabricated and is positive in opera.- tion.

Although a particular embodiment of the invention has been described in detail herein, it is evident that many variations may be devised within the spirit and scope thereof and the following claims are intended to include such variations.

I claim:

1. In a breech member for a firearm, a firing pin device including a reciprocably mounted cartridge striker member, a reciprocably mounted actuator member, a column of fluid, a first seal to inclose liquid tight the rear end of said column of fluid and to transmit movement between said actuator and said column of fluid, and a second seal to inclose liquid tight the front end of said column of fluid and to transmit movement between said column of fluid and said cartridge striker member.

2. The device of claim 1 with said first seal being secured to said actuator for reciprocation therewith, and said second seal being secured to said cartridge striker member for reciprocation therewith.

3. The device of claim 1 with said first seal being a diaphragm member cooperable with said actuator and said column of fluid for transmitting movement therebetween, and said second seal being a diaphragm member cooperable with said cartridge striker member and said column of fluid for transmitting movement therebetween.

References Cited in the file of this patent UNITED STATES PATENTS 542,540 Simpson July 9, 1895 1,962,591 Haubroe June 12, 1934 2,535,820 Temple Dec. 26, 1950 FOREIGN PATENTS 150,492 Germany June 17, 1904 486,774 Great Britain June 9, 1938 121,450 Sweden Apr. 13, 1948 

